Semiconductor device with floating gate and electrically floating body

ABSTRACT

Techniques for providing floating body memory devices are disclosed. In one particular exemplary embodiment, the techniques may be realized as a semiconductor device comprising a floating gate, a control gate disposed over the floating gate, a body region that is electrically floating, wherein the body region is configured so that material forming the body region is contained under at least one lateral boundary of the floating gate, and a source region and a drain region adjacent the body region.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 13/964,777, filed Aug. 12, 2013, now U.S. Pat. No. 8,792,276,issued Jul. 29, 2014, which is a continuation of U.S. patent applicationSer. No. 12/770,249, filed Apr. 29, 2010, now U.S. Pat. No. 8,508,994,issued Aug. 13, 2013, which claims priority to U.S. Provisional PatentApplication No. 61/174,075, filed Apr. 30, 2009, each of which is herebyincorporated by reference herein in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates to a semiconductor device, architecture,memory cell, array, and techniques for controlling and/or operating suchdevice, cell, and array. More particularly, in one aspect, the presentdisclosure relates to a memory cell, array, architecture and device,wherein the memory cell includes a floating gate and an electricallyfloating body configured or operated to store an electrical charge.

BACKGROUND OF THE DISCLOSURE

There is a continuing trend to employ and/or fabricate advancedintegrated circuits using techniques, materials and devices that improveperformance, reduce leakage current and enhance overall scaling.Semiconductor-on-Insulator (SOI) is a material in which such devices maybe fabricated or disposed on or in (hereinafter collectively “on”). Suchdevices are known as SOI devices and include, for example, partiallydepleted (PD) devices, fully depleted (FD) devices, multiple gatedevices (for example, double or triple gate), and Fin-FET.

One type of dynamic random access memory cell is based on, among otherthings, the electrically floating body effect of SOI transistors; see,for example, U.S. Pat. No. 6,969,662 (the “'662 patent”). In thisregard, the dynamic random access memory cell may consist of a PD or aFD SOI transistor (or transistor formed in bulk material/substrate)having a channel, which is disposed adjacent to the body and separatedfrom the channel by a gate dielectric. The body region of the transistoris electrically floating in view of the insulation layer (ornon-conductive region, for example, in a bulk-type material/substrate)disposed beneath the body region. The state of the memory cell isdetermined by the concentration of charge within the body region of theSOI transistor.

Data is written into or read from a selected memory cell by applyingsuitable control signals to a selected word line(s), a selected sourceline(s) and/or a selected bit line(s). In response, charge carriers areaccumulated in or emitted and/or ejected from electrically floating bodyregion wherein the data states are defined by the amount of carrierswithin electrically floating body region. Notably, the entire contentsof the '662 patent, including, for example, the features, attributes,architectures, configurations, materials, techniques and advantagesdescribed and illustrated therein, are incorporated by reference herein.

Referring to the operations of an N-channel transistor, for example, thememory cell of a DRAM array operates by accumulating in oremitting/ejecting majority carriers (electrons or holes) from bodyregion. In this regard, conventional write techniques may accumulatemajority carriers (in this example, “holes”) in body region of memorycells by, for example, impact ionization near source region and/or drainregion. In sum, conventional writing programming techniques for memorycells having an N-channel type transistor often provide an excess ofmajority carriers by impact ionization or by band-to-band tunneling(gate-induced drain leakage (“GIDL”)). The majority carriers may beemitted or ejected from body region by, for example, forward biasing thesource/body junction and/or the drain/body junction, such that themajority carrier may be removed via drain side hole removal, source sidehole removal, or drain and source hole removal, for example.

Notably, for at least the purposes of this discussion, a logic high datastate, or logic “1”, corresponds to, for example, an increasedconcentration of majority carries in the body region relative to anunprogrammed device and/or a device that is programmed with logic lowdata state, or logic “0”. In contrast, a logic low data state, or logic“0”, corresponds to, for example, a reduced concentration of majoritycarriers in the body region relative to a device that is programmed witha logic high data state, or logic “1”. The terms “logic low data state”and “logic 0” may be used interchangeably herein; likewise, the terms“logic high data state” and “logic 1” may be used interchangeablyherein.

In one conventional technique, the memory cell is read by applying asmall bias to the drain of the transistor as well as a gate bias whichis above the threshold voltage of the transistor. In this regard, in thecontext of memory cells employing N-type transistors, a positive voltageis applied to one or more word lines to enable the reading of the memorycells associated with such word lines. The amount of drain current isdetermined or affected by the charge stored in the electrically floatingbody region of the transistor. As such, conventional reading techniquessense the amount of channel current provided/generated in response tothe application of a predetermined voltage on the gate of the transistorof the memory cell to determine the state of the memory cell; a floatingbody memory cell may have two or more different current statescorresponding to two or more different logical states (for example, twodifferent current conditions/states corresponding to the two differentlogical states: “1” and “0”).

Further to writing and reading data to memory cells, data stored in thememory cells is required, under certain circumstances, to beperiodically refreshed as a result of leakage current. The refreshing ofthe memory generally involves periodically reading information or datafrom an area of the memory (e.g., memory cells), and subsequentlyrewriting the read information into the same area of memory (e.g.,memory cells) from which it was read with no modifications. Conventionalrefreshing techniques thus use the read and write operations appropriateto the transistor, and perform the read and write during two or moreseparate clock cycles. The technique used for refreshing data in adynamic memory can have a large impact on memory performance, includingmemory availability, die area, and power consumption. Memories aretypically and more specifically refreshed by performing a read operationduring which data is read from memory cells into sense amps, followed bya write operation during which data is written back into the memorycells.

Conventional solutions to improve memory availability have typicallyinvolved increasing the number of sense amps in the memory so more ofthe memory can be refreshed at the same time. Unfortunately, theaddition of more sense amps increases memory die area. Additionally,conventional refresh techniques often lead to relatively large powerconsumption due to, for example, the separate read and write operationsof the refresh.

In view of the foregoing, it may be understood that there may besignificant problems and shortcomings associated with current floatingbody memory technologies.

SUMMARY OF THE DISCLOSURE

Techniques for providing floating body memory devices are disclosed. Inone particular exemplary embodiment, the techniques may be realized as asemiconductor device comprising a floating gate, a control gate disposedover the floating gate, a body region that is electrically floating,wherein the body region is configured so that material forming the bodyregion is contained under at least one lateral boundary of the floatinggate, and a source region and a drain region adjacent the body region.

In another particular exemplary embodiment, the techniques may berealized as a semiconductor device comprising a floating gate, a controlgate disposed over the floating gate, a body region that is electricallyfloating, wherein the body region is configured so that material formingthe body region extends beyond at least one lateral boundary of thefloating gate, and a source region and a drain region adjacent the bodyregion.

In another particular exemplary embodiment, the techniques may berealized as a semiconductor device comprising a control gate, a floatinggate partially disposed under the control gate, a body region partiallydisposed under the floating gate, wherein the body region iselectrically floating, and a source region and a drain region adjacentthe body region, wherein one or more of the source region and the drainregion include a doped region shaped so that a farthermost boundary ofthe doped region is separated from a portion of the body regionunderlying the floating gate.

In another particular exemplary embodiment, the techniques may berealized as a semiconductor device comprising a body region configuredto be electrically floating, a floating gate disposed over a firstportion of the body region, a control gate disposed over the floatinggate, a source region adjoining a second portion of the body region,wherein the second portion is adjacent the first portion and separatingthe source region from the first portion, and a drain region adjoining athird portion of the body region, wherein the third portion is adjacentthe first portion and separating the drain region from the firstportion.

In another particular exemplary embodiment, the techniques may berealized as a transistor comprising a floating body region on ainsulating substrate, a floating gate disposed over a portion of thefloating body region, and a source region and a drain region, wherein adoping profile of one or more of the source and the drain region isconfigured to prevent formation of a contiguous current channelextending between the source region and the drain region through thefloating body region.

In another particular exemplary embodiment, the techniques may berealized as a method for forming a transistor, comprising forming asemiconductor on an insulator, forming a first gate over a first portionof the semiconductor and electrically isolating the first gate from thesemiconductor, forming a second gate over a portion of the first gateand electrically isolating the second gate from the first gate, formingspacers over a second portion and a third portion of the semiconductor,wherein the spacers adjoin the insulating layer and the first portion,second portion, and third portion form a floating body region, forming asource region by implanting an impurity into a fourth portion of thesemiconductor after forming the spacers, wherein the fourth portion isadjacent the second portion, and forming a drain region by implantingthe impurity into a fifth portion of the semiconductor after forming thespacers, wherein the fifth portion is adjacent the third portion.

In another particular exemplary embodiment, the techniques may berealized as a semiconductor circuit device produced by a methodcomprising forming a semiconductor on an insulator, forming a first gateover a first portion of the semiconductor and electrically isolating thefirst gate from the semiconductor, forming a second gate over a portionof the first gate and electrically isolating the second gate from thefirst gate, forming spacers over a second portion and a third portion ofthe semiconductor, wherein the spacers adjoin the insulating layer andthe first portion, second portion, and third portion form a floatingbody region, forming a source region by implanting an impurity into afourth portion of the semiconductor after forming the spacers, whereinthe fourth portion is adjacent the second portion, forming a drainregion by implanting the impurity into a fifth portion of thesemiconductor after forming the spacers, wherein the fifth portion isadjacent the third portion.

In another particular exemplary embodiment, the techniques may berealized as a semiconductor device comprising a body region, wherein thebody region is electrically floating, a gate disposed over a firstportion of the body region, wherein the gate is electrically floating, asource region adjoining a second portion of the body region, wherein thesecond portion is adjacent the first portion and separating the sourceregion from the first portion, and a drain region adjoining a thirdportion of the body region, wherein the third portion is adjacent thefirst portion and separating the drain region from the first portion.

In another particular exemplary embodiment, the techniques may berealized as an integrated circuit device comprising a memory cellincluding a transistor, wherein the transistor comprises a body regionconfigured to be electrically floating, a floating gate disposed over afirst portion of the body region, a control gate disposed over thefloating gate, a source region adjoining a second portion of the bodyregion, wherein the second portion is adjacent the first portion andseparating the source region from the first portion, and a drain regionadjoining a third portion of the body region, wherein the third portionis adjacent the first portion and separating the drain region from thefirst portion, and control circuitry coupled to the memory cell, whereinthe control circuitry to apply a first signal set to the memory cell tocause the memory cell to operate as a non-volatile memory cell, whereinthe control circuitry to apply a second signal set to the memory cell tocause the memory cell to operate as a volatile memory cell.

The present disclosure will now be described in more detail withreference to exemplary embodiments thereof as shown in the accompanyingdrawings. While the present disclosure is described below with referenceto exemplary embodiments, it should be understood that the presentdisclosure is not limited thereto. Those of ordinary skill in the arthaving access to the teachings herein will recognize additionalimplementations, modifications, and embodiments, as well as other fieldsof use, which are within the scope of the present disclosure asdescribed herein, and with respect to which the present disclosure maybe of significant utility.

BRIEF DESCRIPTION OF THE DRAWINGS

In the course of the detailed description to follow, reference will bemade to the attached drawings. These drawings show different aspects ofthe present disclosure and, where appropriate, reference numeralsillustrating like structures, components, materials and/or elements indifferent figures are labeled similarly. It is understood that variouscombinations of the structures, components, materials and/or elements,other than those specifically shown, are contemplated and are within thescope of the present disclosure.

Moreover, there are many aspects of the present disclosure described andillustrated herein. The present disclosure is not limited to any singleaspect or embodiment thereof, nor to any combinations and/orpermutations of such aspects and/or embodiments. Moreover, each of theaspects of the present disclosure, and/or embodiments thereof, may beemployed alone or in combination with one or more of the other aspectsof the present disclosure and/or embodiments thereof. For the sake ofbrevity, many of those permutations and combinations will not bediscussed separately herein.

FIG. 1A shows a floating gate transistor in accordance with anembodiment of the present disclosure.

FIG. 1B shows a floating gate transistor in accordance with anembodiment of the present disclosure.

FIG. 2 shows a floating gate transistor in accordance with an embodimentof the present disclosure.

FIG. 3 shows operation of the transistor as a flash memory device whenwriting or programming logic “1” using hot hole injection in accordancewith an embodiment of the present disclosure.

FIG. 4 shows operation of the transistor as a flash memory device whenwriting or programming logic “0” using hot electron injection inaccordance with an embodiment of the present disclosure.

FIG. 5 shows operation of the transistor as a flash memory device whenwriting or programming logic “1” using electron tunneling in accordancewith an embodiment of the present disclosure.

FIG. 6 shows operation of the transistor as a flash memory device whenwriting or programming logic “0” using electron tunneling in accordancewith an embodiment of the present disclosure.

FIG. 7 shows operation of the transistor operating as a flash memorydevice when reading data of the transistor in accordance with anembodiment of the present disclosure.

FIG. 8 shows operation of the transistor operating as a flash memorydevice when reading data of the transistor in accordance with analternative embodiment of the present disclosure.

FIG. 9 shows representative control signals along with the cell currentID during operation of transistors as a flash memory device when readingdata of multi-bit flash cells in accordance with another alternativeembodiment of the present disclosure.

FIG. 10 shows operation of the transistor as a DRAM device when writingor programming logic “1” in accordance with an embodiment of the presentdisclosure.

FIG. 11 shows operation of the transistor as a DRAM device when writingor programming logic “0” in accordance with an embodiment of the presentdisclosure.

FIG. 12 shows operation of the transistor operating as a DRAM devicewhen reading data of the transistor in accordance with an embodiment ofthe present disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

There are many aspects of the present disclosure described herein aswell as many embodiments of those aspects. In one aspect, the presentdisclosure may be directed to a semiconductor device including afloating gate and an electrically floating body. In another aspect, thepresent disclosure may be directed to techniques to control and/oroperate a semiconductor memory cell (and memory cell array having aplurality of such memory cells as well as an integrated circuit deviceincluding a memory cell array) having one or more transistors having afloating gate and an electrically floating body in which an electricalcharge is stored in the floating gate or the electrically floating body(according to the mode of operation of the transistor).

The present disclosure may also be directed to semiconductor memorycells, arrays, circuitry and devices to implement such control andoperation techniques. Notably, the memory cell and/or memory cell arraymay comprise a portion of an integrated circuit device, for example,logic device (such as, a microcontroller or microprocessor) or a portionof a memory device (such as, a discrete memory).

FIG. 1A shows a floating gate transistor 10 in accordance with anembodiment of the present disclosure. The transistor 10 includes afloating gate 12 and a body region 14 configured to be electricallyfloating. The body region 14 includes three portions or regions14-1/14-2/14-3 that collectively define the electrically floating body14. Each of the three regions 14-1/14-2/14-3 of the body comprises thesame or similar material (e.g., p-type material, n-type material, etc.).The transistor 10 includes a floating gate 12 disposed over the bodyregion 14.

The floating body region 14 of the floating gate transistor 10 includesa source region 11 adjoining a second portion 14-2 of the body region14; the second portion 14-2 of the body region is adjacent the firstportion 14-1 and separates the source region 11 from the first portion14-1. A drain region 13 adjoins a third portion 14-3 of the body region14; the third portion 14-3 of the body region is adjacent the firstportion 14-1 and separates the drain region 13 from the first portion14-1. The source region 11 and/or drain region 13 is created usingconventional doping or implantation techniques but is not so limited.The second portion 14-2 and third portion 14-3 of the body regionfunction to electrically “disconnect” (e.g., disconnect any charge thatmay accumulate, disconnect any inversion channel that may form) in thefirst portion 14-1 from one or more of the source 11 and the drain 13 asdescribed in detail below.

The transistor 10 of an embodiment includes a floating gate 12 disposedover the body region 14, as described above. The floating gate 12 of anembodiment is disposed over the first portion 14-1 of the body region 14and, additionally, some portion of the second 14-2 and third 14-3portions of the body region. Generally, the floating gate 12 comprises agate dielectric 12D and a dielectric 12X. The gate dielectric 12D ispositioned between the floating gate 12 and the floating body region 14.The oxide 12X isolates the floating gate 12 from the control gate 15 sothat the floating gate of this transistor is electrically isolated fromother components of the device (i.e. no resistive connections are formedto the floating gate 12). Because dielectric surrounds the floating gate12, any charge trapped on the floating gate 12 remains on the floatinggate 12. The charge stored on the floating gate 12 can be modified byapplying voltages to terminals of the source 11, drain 13, body 14 andcontrol gate 15, such that the fields result in phenomena like hotcarrier injection and Fowler-Nordheim tunneling (referred to herein as“tunneling”), as described in detail below.

Data is written into, read from, or refreshed in a selected transistor10 by application of suitable control signals. Control signals arecoupled to the transistor 10 through one of more of a source line SL, abit line BL, and a word line WL. In an embodiment, the control gate of atransistor 10 of an embodiment is connected to a word line WL, thesource region 11 is connected to a source line SL, and the drain region13 is connected to a bit line BL, but the embodiment is not so limited.In response to the control signals, charge carriers are accumulated inor emitted and/or ejected from the floating gate 12 and/or theelectrically floating body region 14 wherein the data states are definedby the amount of carriers within the floating gate 12 and/or theelectrically floating body region 14.

The floating gate transistor 10 of an embodiment can function as a flashmemory device. Furthermore, the floating gate transistor 10 can alsofunction as a dynamic random access (DRAM) memory device. Operations ofthe floating gate transistor 10 as a flash memory device and a DRAMdevice are described in detail below.

FIG. 1B shows a floating gate transistor 10A in accordance with anembodiment of the present disclosure. The transistor 10A includes afloating gate 12A and a body region 14 configured to be electricallyfloating. The body region 14 includes three portions or regions14-1/14-2/14-3 that collectively define the electrically floating body14. Each of the three regions 14-1/14-2/14-3 of the body comprises thesame or similar material (e.g., p-type material, n-type material, etc.).The transistor 10A includes a floating gate 12A disposed over the bodyregion 14.

The floating gate 12A of this alternative embodiment is disposed overthe first portion 14-1 of the body region 14. The floating gate 12Agenerally comprises a gate dielectric 12DA and a dielectric 12XA. Thegate dielectric 12DA is positioned between the floating gate 12A and thefirst portion 14-1 of the floating body region 14. The oxide 12XAisolates the floating gate 12A from the control gate 15A so that thefloating gate 12A of this transistor is electrically isolated from othercomponents of the device. Because dielectric surrounds the floating gate12A, any charge trapped on the floating gate 12A remains on the floatinggate 12A. The charge stored on the floating gate 12A can be modified byapplying voltages to terminals of the source 11, drain 13, body 14 andcontrol gate 15A, as described in detail herein.

Data is written into, read from, or refreshed in a selected transistor10A by application of suitable control signals. Control signals arecoupled to the transistor 10A through one of more of a source line SL, abit line BL, and a word line WL. In an embodiment, the control gate of atransistor 10A of an embodiment is coupled to a word line WL, the sourceregion 11 is coupled to a source line SL, and the drain region 13 iscoupled to a bit line BL, but the embodiment is not so limited. Inresponse to the control signals, charge carriers are accumulated in oremitted and/or ejected from the floating gate 12A and/or theelectrically floating body region 14 wherein the data states are definedby the amount of carriers within the floating gate 12A and/or theelectrically floating body region 14.

The floating gate transistor 10A of an embodiment can function as aflash memory device. Furthermore, the floating gate transistor 10A canalso function as a dynamic random access (DRAM) memory device.Operations of the floating gate transistor 10A as a flash memory deviceand a DRAM device are described in detail below.

The floating gate of an embodiment generally comprises a floating gate12 at least partially surrounded by oxide 12X, as described above. Theoxide 12X isolates the floating gate 12 from the control gate 15 so thatthe floating gate of the host transistor is electrically isolated fromother components of the device (i.e. no resistive connections are formedto the floating gate 12. The gate oxide of an alternative transistorembodiment can comprise silicon nitride (Si₃N₄) inserted inside the gateoxide, thereby forming a Silicon-Oxide-Nitride-Oxide-Silicon (SONOS)memory device. The nitride is non-conductive but contains a large numberof charge trapping sites able to hold an electrostatic charge. Thenitride layer is electrically isolated from the surrounding transistor,although charges stored on the nitride directly affect the conductivityof the underlying transistor channel. The oxide/nitride sandwich cancomprise, for example, a 2 nm thick oxide lower layer, a 5 nm thicksilicon nitride middle layer, and a 5-10 nm oxide upper layer. With theexception of the gate oxide, all other aspects of the SONOS memorydevice are as described above with reference to FIGS. 1A and 1B.

The gate oxide of yet another alternative transistor embodiment cancomprise high-k dielectric (Hi-k) Nitride inserted inside the gateoxide. This combination forms a Silicon Hi-k Nitride Oxide Silicon(SHINOS) memory device. With the exception of the gate oxide, all otheraspects of the SHINOS memory device are as described above withreference to FIGS. 1A and 1B.

More specifically, FIG. 2 shows a floating gate transistor 100 inaccordance with an embodiment of the present disclosure. The transistor100 includes a floating gate 102 and a body region 104 configured to beelectrically floating. The body region 104 includes three portions orregions 104-1/104-2/104-3 that collectively define the electricallyfloating body 104. Each of the three regions 104-1/104-2/104-3 of thebody comprises the same or similar material (e.g., P-type in thisexample). In this embodiment the floating body region 104 comprisesp-type material and the source and drain regions both comprise n-typematerial; alternative embodiments can include a floating body region 104comprising n-type material and source and drain regions both comprisingp-type material. The transistor 100 includes a floating gate 102disposed over the three regions 104-1/104-2/104-3 that collectivelydefine the electrically floating body 104 (e.g., FIG. 1A), but theembodiment is not so limited as described above, such that the floatinggate can be disposed only over the first portion 104-1 of the bodyregion 104 (e.g., FIG. 1B).

The floating body region 104 of the floating gate transistor 100includes a source region 110 adjoining a second portion 104-2 of thebody region 104; the second portion 104-2 of the body region is adjacentthe first portion 104-1 and separates the source region 110 from thefirst portion 104-1. A drain region 130 adjoins a third portion 104-3 ofthe body region 104; the third portion 104-3 of the body region isadjacent the first portion 104-1 and separates the drain region 130 fromthe first portion 104-1. The source region 110 and/or drain region 130is created using conventional doping or implantation techniques but isnot so limited. The second portion 104-2 and third portion 104-3 of thebody region function to electrically “disconnect” (e.g., disconnect anycharge that may accumulate, disconnect any inversion channel that mayform) in the first portion 104-1 from one or more of the source 110 andthe drain 130 as described in detail below.

The floating gate 102 of an embodiment is disposed over the firstportion 104-1 of the body region 104. The floating gate 102 comprises agate dielectric 102D and a dielectric 102X. The gate dielectric 102D ispositioned between the floating gate 102 and the floating body region104. The oxide 102X isolates the floating gate 102 from the control gate105 so that the floating gate of this transistor is electricallyisolated from other components of the device (i.e. no resistiveconnections are formed to the floating gate 102). Because dielectricsurrounds the floating gate, any charge trapped on the floating gate 102remains on the floating gate 102. The charge stored on the floating gate102 can be modified by applying voltages to terminals of the source 110,drain 130, body 104 and control gate 105, such that the fields result inphenomena like hot carrier injection and Fowler-Nordheim tunneling(referred to herein as “tunneling”), as described in detail below.

The floating gate transistor 100 of an embodiment can function as aflash memory device. Furthermore, the floating gate transistor 100 canalso function as a dynamic random access (DRAM) memory device. Operationof the floating gate transistor 100 is as a flash memory device or aDRAM device is described in detail below. The operational examples thatfollow below make reference to an N-channel transistor 100 that includesa floating gate disposed over the three regions that collectively definethe electrically floating body (e.g., FIG. 1A); it is understood,however, that the examples are not so limited as described above, andthe floating gate can be disposed only over the first portion of thebody region (e.g., FIG. 1B).

FIG. 3 shows operation of the transistor 100 as a flash memory devicewhen writing or programming logic “1” using hot hole injection inaccordance with an embodiment of the present disclosure. The transistor100 of this embodiment is an N-channel or nMOS FET, as described above,but is not so limited (e.g., transistor 100 may be a P-channel or pMOSFET in an alternative embodiment). The N-channel device includes source110 and drain 120 regions comprising N+-type material while the bodyregion 104 comprises a P-type material.

A logic “1” programming operation of an embodiment of the transistoroperating as a flash memory device is carried out using hot holeinjection through the application of control signals. Control signalshaving predetermined voltages (for example, Vg=−5 v, Vs=0.0 v, andVd=3.5 v) are applied to the control gate, source region 110 and drainregion 120 (respectively) of transistor 100. The control signals resultin an accumulation of minority carriers in the electrically floatingbody 104. The minority carriers of the body region 104 accumulate in thefirst portion 104-1 of the body region 104. The minority carriers mayaccumulate in an area of the first portion 104-1 under the floating gate102, but are not so limited.

The control signals also result in a source current in the electricallyfloating body region 104 of transistor 100. More specifically, thepotential difference between the source voltage and the drain voltage(e.g., 3.5 volts) is greater than the threshold required to turn on thebipolar transistor 100. Therefore, source current of the transistor 100causes or produces impact ionization and/or the avalanche multiplicationphenomenon among particles (accumulated minority carriers) in theelectrically floating body region 104. The impact ionization produces,provides, and/or generates an excess of majority carriers (not shown) inthe electrically floating body region 104 of transistor 100. The sourcecurrent responsible for impact ionization and/or avalanchemultiplication in the electrically floating body region 104 is initiatedor induced by the control signal applied to gate 102 of transistor 100along with the potential difference between the source 110 and drain 120regions. Such a control signal may induce channel impact ionizationwhich raises or increases the potential of body region 104 and “turnson”, produces, causes and/or induces a source current in transistor 100.

The magnitude of the control signals applied to the control gate, source110, and drain 120 result in a charge being stored on the floating gate102 as a result of hot carrier injection from the body region 104 thatis in the “on” state. Hot carrier injection is the phenomenon insolid-state devices or semiconductors where a majority carrier (e.g.,“holes”) gains sufficient kinetic energy to overcome a potentialbarrier, becoming a “hot carrier”, and then migrates to a different areaof the device. More particularly, in this embodiment, the hot carriergains sufficient kinetic energy to overcome the potential barrier of thebody region 104, and then migrates from the body region 104 through thegate oxide to the floating gate. In this device, “hot carrier” thereforerefers to the effect where the majority carrier (e.g., “holes”) isinjected from the floating body region 104 to the floating gate 102 (notshown on FIG. 3). As a result of the polarity (e.g., negative) of thecontrol signal applied to the floating gate 102, majority carriers thatgain sufficient kinetic energy to become “hot” enter the valence band ofthe dielectric from the first portion 104-1 of the body 104 andaccumulate on the floating gate 102.

The majority carriers, once injected from the floating body region 104,reside at the floating gate 102 where in memory terms they represent a“1”, or logic high state, until such time as the memory is erased, andthe majority carrier is removed from the floating gate 102. Thus, inthis embodiment, the predetermined voltages of the applied controlsignals program or write logic “1” in the transistor 100 via impactionization and avalanche multiplication in the electrically floatingbody region 104, and hot carrier injection from the floating body region104 to the floating gate 102.

FIG. 4 shows operation of the transistor 100 as a flash memory devicewhen writing or programming logic “0” using hot electron injection inaccordance with an embodiment of the present disclosure. The transistor100 of this embodiment is an N-channel or nMOS FET, as described above,but is not so limited (e.g., transistor 100 may be a P-channel or pMOSFET in an alternative embodiment). The N-channel device includes source110 and drain 120 regions comprising N+-type material while the bodyregion 104 comprises a P-type material.

A logic “0” programming operation of an embodiment of the transistoroperating as a flash memory device is carried out using hot electroninjection through the application of control signals. Control signalshaving predetermined voltages (for example, Vg=5 v, Vs=0.0 v, and Vd=3.5v) are applied to the control gate, source region 110 and drain region120 (respectively) of transistor 100. The control signals result in anaccumulation of minority carriers in the electrically floating body 104.The minority carriers of the body region 104 accumulate in the firstportion 104-1 of the body region 104. The minority carriers mayaccumulate in an area of the first portion 104-1 under the floating gate102, but are not so limited.

The control signals also result in a source current in the electricallyfloating body region 104 of transistor 100. More specifically, thepotential difference between the source voltage and the drain voltage(e.g., 3.5 volts) is greater than the threshold required to turn on thebipolar transistor 100. Therefore, source current of the transistor 100causes or produces impact ionization and/or the avalanche multiplicationphenomenon among particles (accumulated minority carriers) in theelectrically floating body region 104. The impact ionization produces,provides, and/or generates an excess of majority carriers in theelectrically floating body region 104 of transistor 100. The sourcecurrent responsible for impact ionization and/or avalanchemultiplication in the electrically floating body region 104 is initiatedor induced by the control signal applied to gate 102 of transistor 100along with the potential difference between the source 110 and drain 120regions. Such a control signal may induce channel impact ionizationwhich raises or increases the potential of body region 104 and “turnson”, produces, causes and/or induces a source current in transistor 100.

The magnitude of the control signals applied to the control gate, source110, and drain 120 result in a charge being stored on the floating gate102 as a result of hot carrier injection from the body region 104 thatis in the “on” state. In this embodiment, the hot carrier gainssufficient kinetic energy to overcome the potential barrier of the bodyregion 104, and then migrates from the body region 104 through the oxide102X to the gate dielectric 102D. In the device of this embodiment, “hotcarrier” therefore refers to the effect where the minority carrier(e.g., “electrons”) is injected from the floating body region 104 tocontrol gate. As a result of the polarity (e.g., positive) of thecontrol signal applied to the control gate, majority carriers that gainsufficient kinetic energy to become “hot” and enter the conduction bandof the dielectric from the first portion 104-1 of the body 104accumulate in the gate dielectric 102D and, thus, on the floating gate102. The minority carriers, or electrons, once injected from thefloating body region 104 to the gate dielectric 102D, reside at thefloating gate 102 where in memory terms they represent a “0”, or logiclow state, until such time as the memory is erased, and the majoritycarrier is removed from the floating gate 102. Thus, in this embodiment,the predetermined voltages of the applied control signals program orwrite logic “0” in the transistor 100 via impact ionization andavalanche multiplication in the electrically floating body region 104,and hot carrier injection from the floating body region 104 to thefloating gate 102.

FIG. 5 shows operation of the transistor 100 as a flash memory devicewhen writing or programming logic “1” using electron tunneling inaccordance with an embodiment of the present disclosure. The transistor100 of this embodiment is an N-channel or nMOS FET, as described above,but is not so limited (e.g., transistor 100 may be a P-channel or pMOSFET in an alternative embodiment). The N-channel device includes source110 and drain 120 regions comprising N+-type material while the bodyregion 104 comprises a P-type material.

A logic “1” programming operation of an embodiment of the transistoroperating as a flash memory device is carried out using electrontunneling through the application of control signals. Control signalshaving predetermined voltages (for example, Vg=−10 v, Vs=0.0 v, andVd=0.0 v) are applied to gate 102, source region 110 and drain region120 (respectively) of transistor 100. The control signals prevent sourcecurrent from flowing in the electrically floating body region 104 oftransistor 100. More specifically, the potential difference between thesource voltage and the drain voltage (e.g., 0 volts) is less than thethreshold required to turn on the bipolar transistor 100. Therefore, thetransistor remains in an “off” state such that no source current isproduced and/or induced in transistor 100.

Tunneling, also referred to as Fowler-Nordheim tunneling, is a processin which electrons are transported through a barrier and results inalteration of the placement of electrons in the floating gate. Inaddition to the effect of the control signals applied to the source anddrain of the transistor 100, as described above, the electrical chargeapplied to the floating gate causes the floating gate transistor 100 toact like an electron gun. As a result of the polarity (e.g., negative)of the control signal applied to the floating gate, the electrons of thefloating gate are pushed through, thus removing negative charge from thefloating gate. The floating gate is positively charged as a result ofremoval of the negative charge, and the resultant positive chargeresiding at the floating gate 102 represents, in memory terms, a “1”, orlogic high state, until such time as the memory is erased. Thus, in thisembodiment, the predetermined voltages of the applied control signalsprogram or write logic “1” in the transistor 100 via electron tunnelingfrom the floating gate 102 to the floating body region 104.

FIG. 6 shows operation of the transistor 100 as a flash memory devicewhen writing or programming logic “0” using electron tunneling inaccordance with an embodiment of the present disclosure. The transistor100 of this embodiment is an N-channel or nMOS FET, as described above,but is not so limited (e.g., transistor 100 may be a P-channel or pMOSFET in an alternative embodiment). The N-channel device includes source110 and drain 120 regions comprising N+-type material while the bodyregion 104 comprises a P-type material.

A logic “0” programming operation of an embodiment of the transistoroperating as a flash memory device is carried out using electrontunneling through the application of control signals. Control signalshaving predetermined voltages (for example, Vg=10 v, Vs=0.0 v, andVd=0.0 v) are applied to gate 102, source region 110 and drain region120 (respectively) of transistor 100. The control signals prevent sourcecurrent from flowing in the electrically floating body region 104 oftransistor 100. More specifically, the potential difference between thesource voltage and the drain voltage (e.g., 0 volts) is less than thethreshold required to turn on the bipolar transistor 100. Therefore, thetransistor remains in an “off” state such that no source current isproduced and/or induced in transistor 100.

In addition to the effect of the control signals applied to the sourceand drain of the transistor 100, as described above, the electricalsignal applied to the control gate causes the floating gate transistorto act like an electron gun. As a result of the polarity (e.g.,positive) of the control signal applied to the floating gate, theexcited electrons of the floating body 104 are pushed through thusplacing negative charge on the floating gate. The floating gate isnegatively charged as a result of this addition of negative charge, andthe resultant negative charge residing at the floating gate 102represents, in memory terms, a “0”, or logic low state, until such timeas the memory is erased. Thus, in this embodiment, the predeterminedvoltages of the applied control signals program or write logic “0” inthe transistor 100 via electron tunneling from the floating body 104 tothe floating gate 102.

FIG. 7 shows operation of the transistor 100 operating as a flash memorydevice when reading data of the transistor in accordance with anembodiment of the present disclosure. In one embodiment, the data stateof the transistor may be read and/or determined by applying controlsignals having predetermined voltages to the floating gate, sourceregion and drain region of transistor (for example, Vg=0.0 v, Vs=0.0 vand Vd=2.5 v, respectively). Such control signals, in combination,induce and/or cause a source current in transistors that have a positivecharge on the floating gate (transistors programmed to logic “1”) asdescribed above. As such, sensing circuitry (for example, across-coupled sense amplifier), which is coupled to the transistor,senses the data state using primarily and/or based substantially on thesource current. For those transistors having negative charge on thefloating gate (transistors programmed to logic “0”), such controlsignals induce, cause and/or produce little to no source current (forexample, a considerable, substantial or sufficiently measurable sourcecurrent).

Thus, in response to read control signals, the transistor 100 generatesa source current which is representative of the data state of thetransistor 100. Where the data state is logic high or logic “1”, thetransistor 100 provides a substantially greater source current thanwhere the data state is logic low or logic “0”. The transistor 100 mayprovide little to no source current when the data state is logic low orlogic “0”. Data sensing circuitry determines the data state of thetransistor based substantially on the source current induced, causedand/or produced in response to the read control signals.

FIG. 8 shows operation of the transistor 100 operating as a flash memorydevice when reading data of the transistor in accordance with analternative embodiment of the present disclosure. In this alternativeembodiment, the data state of the transistor 100 may be read and/ordetermined by applying control signals having predetermined voltages tothe floating gate, source region and drain region of transistor (forexample, Vg=3 v, Vs=0.0 v and Vd=0.5 v, respectively). Such controlsignals, in combination, induce and/or cause a channel current intransistors that have a positive charge on the floating gate(transistors programmed to logic “1”) as described above. As such,sensing circuitry (for example, a cross-coupled sense amplifier) (notshown), which is coupled to the transistor 100, senses the data stateusing primarily and/or based substantially on the source current. Forthose transistors having a negative charge on the floating gate(transistors programmed to logic “0”), such control signals induce,cause and/or produce little to no channel current (for example, aconsiderable, substantial or sufficiently measurable source current).

Thus, in response to read control signals, the transistor 100 generatesa channel current which is representative of the data state of thetransistor 100. Where the data state is logic high or logic “1”, thetransistor 100 provides a substantially greater channel current thanwhere the data state is logic low or logic “0”. The transistor 100 mayprovide little to no channel current when the data state is logic low orlogic “0”. Data sensing circuitry determines the data state of thetransistor based substantially on the channel current induced, causedand/or produced in response to the read control signals.

The application of control signals can also be used to read transistorsof an embodiment when used in multi-bit flash cells. Considering asingle transistor, in an embodiment, the voltage of the control signalapplied to the control gate is selected to put the transistor in thesub-threshold regime. In the sub-threshold regime, the bipolartriggering time is very sensitive to the transistor threshold voltageVt. As the threshold voltage Vt is defined by the charge stored in thefloating gate, the bipolar triggering delay Δt provides informationabout charge stored in the floating gate and can be used to read themulti-bit Flash. FIG. 9 shows representative control signals along withthe cell current ID during operation of transistors 100 as a flashmemory device when reading data of multi-bit flash cells in accordancewith another alternative embodiment of the present disclosure.

The floating gate transistor 100 of an embodiment can function as aflash memory device, operations of which were described in detail above.Additionally, the floating gate transistor 100 can also function as aDRAM device, operations of which are described in detail below.

FIG. 10 shows operation of the transistor 100 as a DRAM device whenwriting or programming logic “1” in accordance with an embodiment of thepresent disclosure. The transistor 100 of this embodiment is anN-channel or nMOS FET, as described above, but is not so limited;transistor 100 may be a P-channel or pMOS FET in an alternativeembodiment.

A logic “1” programming operation of an embodiment of the transistoroperating as a DRAM device is carried out through the application ofcontrol signals. In operation, when writing or programming logic “1”, inone embodiment, control signals having predetermined voltages (forexample, Vg=−3 v, Vs=0.0 v, and Vd=2.5 v) are applied to gate, sourceregion and drain region (respectively) of transistor 100. The controlsignals may result in an accumulation of minority carriers in theelectrically floating body. As a result of the control signal applied tothe gate, any minority carriers that happen to be present in the bodyregion accumulate in the first portion of the body. The minoritycarriers may accumulate in an area of the first portion under the gate,but are not so limited.

The control signals also generate or provide a source current inelectrically floating body region of transistor 100. More specifically,the potential difference between the source voltage and the drainvoltage (e.g., 2.5 volts) is greater than the threshold required to turnon the bipolar transistor. Therefore, source current of the transistorcauses or produces impact ionization and/or the avalanche multiplicationphenomenon among particles in the electrically floating body region. Theimpact ionization produces, provides, and/or generates an excess ofmajority carriers in the electrically floating body region of transistor100.

Notably, it is preferred that the source current responsible for impactionization and/or avalanche multiplication in electrically floating bodyregion is initiated or induced by the control signal applied to gate oftransistor 100 along with the potential difference between the sourceand drain regions. Such a control signal may induce channel impactionization which raises or increases the potential of body region and“turns on”, produces, causes and/or induces a source current intransistor 100. One advantage of the proposed writing/programmingtechnique is that a large amount of the excess majority carriers may begenerated and stored in electrically floating body region of transistor100.

As a result of the polarity (e.g., negative) of the control signalapplied to the gate, the majority carriers of the body region accumulatenear the surface of the first portion of the body region. The polarityof the gate signal (e.g., negative) combined with the floating bodycauses the majority carriers to become trapped or “stored” near thesurface of the first portion of the body region. In this manner the bodyregion of the transistor “stores” charge (e.g., equivalently, functionslike a capacitor). Thus, in this embodiment, the predetermined voltagesof the control signals program or write logic “1” in transistor 100 viaimpact ionization and/or avalanche multiplication in electricallyfloating body region.

FIG. 11 shows operation of the transistor 100 as a DRAM device whenwriting or programming logic “0” in accordance with an embodiment of thepresent disclosure. A logic “0” programming operation of an embodimentof the transistor operating as a DRAM device is carried out through theapplication of control signals. In operation, when writing orprogramming logic “0”, in one embodiment, control signals havingpredetermined voltages (for example, Vg=5 v, Vs=0.0 v, and Vd=0.0 v) areinitially applied to gate, source region and drain region (respectively)of transistor 100. The control signals may result in an accumulation ofminority carriers in the electrically floating body.

The potential difference between the source voltage and the drainvoltage (e.g., 0 volts) of the control signals, however, is less thanthe threshold required to turn on transistor 100. Consequently, noimpact ionization takes place among particles in the body region and nobipolar or source current is produced in the electrically floating bodyregion. Thus, no excess of majority carriers are generated in theelectrically floating body region of transistor 100.

The polarity (e.g., positive) of the gate signal may result in anyminority carriers that accumulate being removed from electricallyfloating body region of transistor 100 via one or more of the sourceregion and the drain region. The result is an absence of excess majoritycarriers in the body region so that, in this manner, the predeterminedvoltages of the control signals program or write logic “0” in thetransistor 100.

FIG. 12 shows operation of the transistor 100 operating as a DRAM devicewhen reading data of the transistor in accordance with an embodiment ofthe present disclosure. In one embodiment, the data state of thetransistor may be read and/or determined by applying control signalshaving predetermined voltages to the floating gate, source region anddrain region of transistor (for example, Vg=−1 v, Vs=0.0 v and Vd=2.5 v,respectively). Such control signals, in combination, induce and/or causea source current in transistors that are programmed to logic “1” asdescribed above. As such, sensing circuitry (for example, across-coupled sense amplifier) (not shown), which is coupled totransistor 100 (for example, drain region 22), senses the data stateusing primarily and/or based substantially on the source current. Forthose transistors that are programmed to logic “0”, such control signalsinduce, cause and/or produce little to no source current (for example, aconsiderable, substantial or sufficiently measurable source current).

Thus, in response to read control signals, transistor 100 generates asource current which is representative of the data state of thetransistor 100. Where the data state is logic high or logic “1”,transistor 100 provides a substantially greater source current thanwhere the data state is logic low or logic “0”. Transistor 100 mayprovide little to no source current when the data state is logic low orlogic “0”. Data sensing circuitry determines the data state of thetransistor based substantially on the source current induced, causedand/or produced in response to the read control signals.

The voltage levels described herein as control signals to implement thewrite and/or read operations are provided merely as examples, and theembodiments described herein are not limited to these voltage levels.The indicated voltage levels may be relative or absolute. Alternatively,the voltages indicated may be relative in that each voltage level, forexample, may be increased or decreased by a given voltage amount (forexample, each voltage may be increased or decreased by 0.5, 1.0 and 2.0volts) whether one or more of the voltages (for example, the source,drain or gate voltages) become or are positive and negative.

The aspects of the present disclosure may be implemented in anintegrated circuit device (for example, a discrete memory device or adevice having embedded memory) including a memory array having aplurality of memory cells arranged in a plurality of rows and columnswherein each memory cell includes an electrically floating bodytransistor. The memory arrays may comprise N-channel, P-channel and/orboth types of transistors. Indeed, circuitry that is peripheral to thememory array (for example, data sense circuitry (for example, senseamplifiers or comparators), memory cell selection and control circuitry(for example, word line and/or source line drivers), as well as row andcolumn address decoders) may include P-channel and/or N-channel typetransistors.

The programming and reading techniques described herein may be used inconjunction with a plurality of memory cells arranged in an array ofmemory cells. A memory array implementing the structure and techniquesof the present disclosure may be controlled and configured including aplurality of memory cells having a separate source line for each row ofmemory cells (a row of memory cells includes a common word line). Thememory array may use any of the example programming, holding and/orreading techniques described herein. The memory arrays may compriseN-channel, P-channel and/or both types of transistors. Circuitry that isperipheral to the memory array (for example, sense amplifiers orcomparators, row and column address decoders, as well as line drivers(not illustrated herein)) may include P-channel and/or N-channel typetransistors. Where P-channel type transistors are employed as memorycells in the memory array(s), suitable write and read voltages (forexample, negative voltages) are well known to those skilled in the artin light of the present disclosure.

The transistors, memory cells, and/or memory array(s) described hereinmay be fabricated using well known techniques and/or materials. Indeed,any fabrication technique and/or material, whether now known or laterdeveloped, may be employed to fabricate the transistors, memory cells,and/or memory array(s). For example, embodiments of the presentdisclosure may employ silicon, germanium, silicon/germanium, galliumarsenide or any other semiconductor material (whether bulk-type or SOI)in which transistors may be formed. As such, the transistors, memorycells, and/or memory array(s) may be disposed on or in (collectively“on”) SOI-type substrate or a bulk-type substrate.

Further, memory array(s) may be comprised of N-channel, P-channel and/orboth types of transistors, as well as partially depleted and/or fullydepleted type transistors. For example, circuitry that is peripheral tothe memory array (for example, sense amplifiers or comparators, row andcolumn address decoders, as well as line drivers (not illustratedherein)) may include FD-type transistors (whether P-channel and/orN-channel type). Alternatively, such circuitry may include PD-typetransistors (whether P-channel and/or N-channel type). There are manytechniques to integrate both PD and/or FD-type transistors on the samesubstrate. All such techniques, whether now known or later developed,are intended to fall within the scope of the present disclosure. WhereP-channel type transistors are employed as memory cells in the memoryarray(s), suitable write and read voltages (for example, negativevoltages) are well known to those skilled in the art in light of thepresent disclosure.

Notably, transistor 100 may be a symmetrical or non-symmetrical device.Where transistor 100 is symmetrical, the source and drain regions areessentially interchangeable. However, where transistor 100 is anon-symmetrical device, the source or drain regions of transistor 100have different electrical, physical, doping concentration and/or dopingprofile characteristics. As such, the source or drain regions of anon-symmetrical device are typically not interchangeable. Thisnotwithstanding, the drain region of the transistor 100 (whether thesource and drain regions are interchangeable or not) is that region ofthe transistor that is connected to the bit line/sense amplifier.

There are many aspects of the present disclosure described andillustrated herein. While certain embodiments, features, attributes andadvantages of the present disclosure have been described andillustrated, it should be understood that many others, as well asdifferent and/or similar embodiments, features, attributes andadvantages of the present disclosure, are apparent from the descriptionand illustrations. As such, the embodiments, features, attributes andadvantages of the present disclosure described and illustrated hereinare not exhaustive and it should be understood that such other, similar,as well as different, embodiments, features, attributes and advantagesof the present disclosure are within the scope of the presentdisclosure.

As mentioned above, the illustrated/example voltage levels to implementthe read and write operations are merely examples. The indicated voltagelevels may be relative or absolute. Alternatively, the voltagesindicated may be relative in that each voltage level, for example, maybe increased or decreased by a given voltage amount (for example, eachvoltage may be increased or decreased by 0.1, 0.15, 0.25, 0.5, 1 volt)whether one or more of the voltages (for example, the source, drain orgate voltages) become or are positive and negative.

As mentioned above, each of the aspects of the present disclosure,and/or embodiments thereof, may be employed alone or in combination withone or more of such aspects and/or embodiments. For the sake of brevity,those permutations and combinations will not be discussed separatelyherein. As such, the present disclosure is not limited to any singleaspect (or embodiment thereof), nor to any combinations and/orpermutations of such aspects and/or embodiments.

Moreover, the above embodiments of the present disclosure are merelyexample embodiments. They are not intended to be exhaustive or to limitthe present disclosure to the precise forms, techniques, materialsand/or configurations disclosed. Many modifications and variations arepossible in light of the above teaching. It is to be understood thatother embodiments may be utilized and operational changes may be madewithout departing from the scope of the present disclosure. As such, theforegoing description of the example embodiments of the presentdisclosure have been presented for the purposes of illustration anddescription. Many modifications and variations are possible in light ofthe above teaching. It is intended that the scope of the presentdisclosure not be limited solely to the description above.

The invention claimed is:
 1. A semiconductor device comprising: afloating gate; a control gate disposed over the floating gate; a bodyregion that is electrically floating, wherein the body region isdisposed beneath the floating gate and configured so that materialforming the body region extends beyond at least one lateral boundary ofthe floating gate; a source region disposed adjacent a first portion ofthe body region; and a drain region disposed adjacent a second portionof the body region.
 2. The device of claim 1, wherein the floating gateis separated from the body region by a dielectric.
 3. The device ofclaim 1, wherein the control gate is separated from the floating gate bya dielectric.
 4. The device of claim 1, wherein the body regioncomprises a first type of semiconductor material.
 5. The device of claim4, wherein the source region comprises a second type of semiconductormaterial different from the first type of semiconductor material.
 6. Thedevice of claim 5, wherein the drain region comprises the second type ofsemiconductor material.
 7. The device of claim 4, wherein the sourceregion comprises the first type of semiconductor material doped withimpurities.
 8. The device of claim 7, wherein the drain region comprisesthe second type of semiconductor material doped with impurities.
 9. Thedevice of claim 8, wherein the source region and the drain region have acommon first doping polarity.
 10. The device of claim 9, wherein thesource region and the drain region are doped with donor impurities. 11.The device of claim 9, wherein the source region and the drain regionare doped with acceptor impurities.
 12. The device of claim 9, whereinthe source region and the drain region have different dopingconcentrations.
 13. The device of claim 9, wherein the body region has asecond polarity different from the first doping polarity.
 14. The deviceof claim 1, wherein the source region is disposed outside of a lateralboundary of the floating gate.
 15. The device of claim 14, wherein thedrain region is disposed outside of the lateral boundary of the floatinggate.
 16. The device of claim 14, wherein at least a portion of thedrain region is disposed inside of the lateral boundary of the floatinggate.
 17. The device of claim 1, wherein the drain region is disposedoutside of a lateral boundary of the floating gate.
 18. The device ofclaim 17, wherein the source region is disposed outside of the lateralboundary of the floating gate.
 19. The device of claim 17, wherein atleast a portion of the source region is disposed inside of the lateralboundary of the floating gate.
 20. The device of claim 1, furthercomprising circuitry to apply a first signal set including a firstpotential difference coupled between the source region and the drainregion and a first gate signal coupled to the control gate, wherein thefirst signal set programs a first logic state in the floating gate. 21.The device of claim 20, further comprising circuitry to apply a secondsignal set including a second potential difference coupled between thesource region and the drain region and a second gate signal coupled tothe control gate, wherein the second signal set programs a second logicstate in the floating gate.
 22. The device of claim 21, furthercomprising circuitry to apply a third signal set including a thirdpotential difference coupled between the source region and the drainregion and a third gate signal coupled to the control gate, wherein thethird signal set reads a logic state in the floating gate.
 23. Thedevice of claim 22, further comprising circuitry to apply a fourthsignal set including a fourth potential difference coupled between thesource region and the drain region and a fourth gate signal coupled tothe control gate, wherein the fourth signal set programs a logic statein the body region.
 24. The device of claim 23, further comprisingcircuitry to apply a fifth signal set including a fifth potentialdifference coupled between the source region and the drain region and afifth gate signal coupled to the control gate, wherein the fifth signalset reads a logic state in the body region.